The National Ribat University

Faculty of Graduate Studies & Scientific Research

Normal Acromioclavicular Joint Morphology In

Sudanese People

(A Radiographic Study)

A Thesis Submitted in Partial Fulfillment Required for M.Sc in

Human Clinical Anatomy

By: Khalid Mohamed Abdelhafiz

Supervisor: Dr. Kamal Eldin Elbadawi

1439- 2017

I

: تعالى قال

(114)ةيلاهـــطةروس

II

ACKNOWLEDGEMENTS

First and before all, my great thanks and prayers to ALLAH for giving me the

ability to do and complete this work.

Wondering around looking for proper words to thank the main supervisor of

this research, Professor Kamal Eldin Elbadawi Babiker, who paved the way not

only for me but also for many students in this university to complete their post

graduatestudiesinaproperway.Wordsarepowerlesstoexpressmyendlessgratitude and

appreciation for the great support and kind advices given by thehim.

Finally,itisnoneedtosaythatthisworkcouldnothavebeenpossiblewithout the

continuous and generous support and encouragement of my lovely family, and their

nice patience andcooperation.

I say thank you all very much…

III

DEDICATION

To

my lovely family,

who

keepsupportingmeallthroughmyway

withtheirloveandkindcare..

Great thanks

and

best wishes ..

IV

مستخلصالدراسة

تهدف هذه الدراسة التحليلية الوصفية بأثر رجعي إلى التحقق في التشكل التشريحي الطبيعي للمفصل األخرمي

نية. هذهاألشعة السيتم فحصهمببين السودانيين. شملت الدراسة مائتي مفصل أخرمي ترقوي ا للترقوة إشعاعي

تراوحت بين عاما ) 54عمارهم أمن اإلناث، متوسط 55منهم ذكور و 55، شخصمائة لحواليالمفاصل تنتمي

الدانية، )بعاد . تم تصنيف المفصل من خالل مالحظة النهاية األخرمية والترقوية للمفصل وقياس األ( عاما 07و 81

فت نوالمسافات الطولية للمفصل، كما تم حساب المسافة المشتركة المتكاملة للمفصل. وقد ص (ةقاصيالمتوسطة، ال

إلى تسعة أنواع: مسطح/ مسطح، مسطح/ منحني، السطوح المفصليةشكال أهذه الدراسة المفصل معتمدة على

ح مسطح/ منحرف، منحرف/ منحرف، منحرف/ مسطح، منحرف/ منحني، منحني/ منحني، منحني / مسط

بين كل من الذكور واإلناث هو النوع المسطح/ المنحني. ال النوع األكثر شيوعا وإتضح أن ومنحني/ منحرف.

لمسافة ن اأصت الدراسة إلى ل ة بالجانبين األيمن واأليسر. كما خ تعلقتوجد فروقات في األنواع والمسافات الم

(، بينما كانت نقطة المسافة 7..0-8مم ) 5.71ة قاصيال(، المسافة 1.77 - 8.5مم ) 5.75ة الطبيعية للمفصل دانيال

وتم إستخدام هذه المسافات الثالثة المذكورة في تحديد محصلة المسافة (. 7..0 - 8.87مم ) 1..4المتوسطة

ن جميع أوحظ (. كما ل 0.50 - 8.44مم ) 1..5كانت و التي المشتركة المتكاملة للمفصل األخرمي الترقوي

يزداد لذياخفض مع تقدم السن باستثناءطول مسافة المفصل أنها تنفي الذكور منها في اإلناث والمساحات أوسع

مع تقدم السن.

V

Abstract

Acromioclavicularjoint(ACJ)isaplanesynovialjoint,withafibrocartilaginousdisc

initsintraarticularspace.Itisoneofthejointsthatconnecttheaxialandappendicular

skeletons. This study was aimed to evaluate radiologically the normal ACJ

morphological anatomy among the Sudanese population. It has been designed as a

descriptive retrospective analytic study. Two hundred normal ACJs X-rays belongto

one hundred subjects, 55 were male and 45 were female, with an average age of 43

ranged from (18 to 70) yrs were studied. The joint type was classified by observing

the acromial and clavicular ends of the joints. The proximal/middle/distal and

longitudinal distances were measured, moreover the integral joint space was

calculated. The present study had classified the morphology of ACJs into nine types

depending on their articular surfaces shape (acromial/ clavicular), which are flat/flat,

flat/ curved, flat/ oblique, oblique/ oblique, oblique/ flat, oblique/ curved, curved/

curved,curved/flatandcurved/obliquetype.ThemostcommontypeofACJinboth

maleandfemalewastheflat/curvedtype.Therewasnosignificantdifferenceintypes and

distances related to right and left sides. The average of the normal proximal distance

was 5.09 mm ranging from (1.9 – 8.00), the distal distance was 4.08 mm ranging from

(1- 7.20), whereas the average of the middle point distance was 3.68 mm ranging from

(1.10 – 7.20). The integral ACJ space was 4.28 mm ranging from (1.33 – 7.47), which

was calculated by using the average of these three mentioned

distances.Comparativelyallspaceswerewiderinmalethanfemale,furthermore,the

reduction in ACJ space was associated with age advance. However, the longitudinal

length was distance increasing with ageadvanced.

VI

List of abbreviations

AC Acromioclavicular

ACJ Acromioclavicular joint

CC Coracoclavicular

DD Distal distance

Fig Figure

ISD Integral space distance

ISD-LM Integral ACJ space – literature method

LL longitudinal length

MPD Middle point distance

mm Millimeter

yrs Years

VII

List of figures

Fig Title Page

2.1 Shows ACJ Types 10

4.1 Shows gender distribution of study group 14

4.2 Shows the age groups distribution of study

Participants 15

4.3 Shows the distribution of ACJ type 17

4.4 Shoulder X-ray, shows flat/ curved type of the

right ACJ 18

4.5 Shoulder X-ray, shows curved/ flat type of the

left ACJ 18

4.6 Shoulder X-ray, shows flat/ flat type of theright

ACJ 18

4.7 Shoulder X-ray, shows oblique/ curved type of

the left ACJ 18

4.8 Shows the distribution of ACJ type among right

& left sides 20

4.9 Shows distribution of right ACJ articularend

shape type among gender 21

4.10 ShowsdistributionofleftACJarticularendshape

type among gender 22

4.11 Shoulder X- ray, shows left ACJ measurements

(PD, MPD, DD) 23

4.12 Shows the means of ACJ (PD, DD and MPD)

measurements among study age groups. 24

4.13 Shows means of ACJ (LL) measures among

study age groups 25

4.13 Shows the means of ISD- LM & ISD comparison

using unpaired t test. 25

VIII

List of tables

Table Title Page

4.1 Shows gender distribution of study group 14

4.2 Shows the age groups distribution of study

Participants 15

4.3 Shows the distribution of ACJ type 16

4.4 Shows distribution of ACJ type among right &

left sides 19

4.5 Shows the distribution of ACJ articular end shape

according to the gender and side 21

4.6 Shows ACJ distances measurements in (mm) 23

4.7 Shows the means of ACJ measurement among

study age groups (mm) 24

4.8 Shows the means of ISD measurements among

study age groups according to gender and side 26

IX

The Contents

Title Page

Alaya I

Acknowledgements II

Dedication III

Abstract in Arabic IV

Abstract in English V

List of Abbreviations VI

List of Figures VII

List of Tables VIII

The Contents IX

Chapter One: Introduction

1.1. Introduction 1

1.2. Justification 2

1.3. Objectives 2

1.3.1.General Objective 2

1.3.2.Specific Objectives 2

Chapter Two: Literature Review

2.1. Anatomy 3

2.2. Acromioclavicular joint pathology 8

2.3. Previousstudies 9

Chapter Three: Material and Methods

3.1. StudyDesign 12

3.2. StudyArea 12

3.3. StudyDuration 12

3.4. StudyPopulation 12

3.4.1. Inclusion criteria 12

3.4.2. Exclusion criteria 12

3.5. Studyvariables 12

3.6. Sampling 13

3.6.1. Sample type 13

X

3.6.2. Sample size 13

3.7. DataCollection 13

3.7.1. Data Collection tools 13

3.7.2. Data management 13

3.8. Ethical Considerations 13

Chapter Four: Results

4.1. Results 14

Chapter Five: Discussion

5.1. Discussion 27

Chapter Six: Conclusion and Recommendations

6.1.Conclusions 30

6.2.Recommendations 31

Chapter Seven: References

References 32

Appendix

Data collection sheet 34

Chapter One

Introduction & Objectives

1

1. Introduction & Objectives

1.1. Introduction:

The shoulder joint complex is composed of four articulations: the

sternoclavicular, acromioclavicular, glenohumeral, and scapulothoracic that

connects the upper limb to the axial skeleton, they work collectively to allow

smooth shoulder function. Together, they allow the shoulder joint to have a wide

rangeofmotionmorethananyjointinthebody,andallthesearticulationsmustbe

respected when managing shoulder dysfunction. The normal function of the

shoulder is a balance between mobility and stability of all these joints. These

studies focus mainly on acromioclavicular joint (ACJ), which one of understudied

joints in literature in comparison with shoulder and sternoclavicular joints in spite

of its varying disorders(1).

AnunderstandingoftheACJanatomyisfundamentaltounderstandinjuriesand

surgical treatments. The ACJ joint is a plane diarthrodial variety of synovial joint,

situated between the lateral end of the clavicle and acromion end of the scapula. It

helps to link the shoulder to the axial skeleton. The articulation surfaces between

thesetwobonescanformathighlyvariableangles(2).Articulationsidesofthisjoint

arecoveredwitharticularcartilage,withafibrocartilaginousdiskinbetween.This

fibrocartilaginous disc is referred to as a meniscal homologue. The degree of disk

completeness varies, with only 10% of individuals having a complete disk(2,3).

The ACJ movements affected by its shape and the repetitiveness of the

movement. The variations of the joint morphology assumed to contribute to

different degrees of attritional damage. Knowledge of ACJ varying morphologies

helps to better understanding of its biomechanics. The purpose of this study is to

describe the normal ACJ morphology on radiograph, to find the prevalence of

particular type (flat, oblique or curved), compare ACJ space diameters (in the

superiorandinferiorendsofthejoints)amonggenderandagegroupsinSudanese

2

subjects, and to assess the similarity of ACJ shape and space diameters on each

side.

1.2. Justification:

ACJ injures & disorders are common and may lead to instability or

degenerative changes requiring surgical intervention. Normal anatomy of the joint

spaceinx-rayisessentialknowledgetodiagnosedislocationsandtodetectarthritic

changes in AC joints. Knowing normal morphometric measurement of joint space

will support decision-making in choosing management modality, emphasize

practicing surgeries and arthroscopes in the shoulder region. Due to lack of

sufficientliteratureonthenormalACJmorphologiesinSundanesepopulation,this

study isinitiated.

1.3. Objectives:

1.3.1. Generalobjective:

To study the radiological morphology of normal ACJ anatomy among the

Sudanese.

1.3.2. Specificobjectives:

1. TofindouttheprevalenceoftheACJtypes(flat,oval,curved)amongstudy

groups.

2. To measure the normal measurement of ACJ space in Sudanesepopulation.

3. To determine the ACJ space differences among different agegroups.

4. To compare the space measurements and shape of ACJ in bothsides.

5. To make a comparison between the measures of ACJ space among males

and females.

6. To provide a data and some literature about the ACJ space in Sudanese

population to be used for furtherstudies.

Chapter Two

Literature Review

2. Literature review:

2.1. Anatomy

2.1.1. Definition ofjoint:

Joints are the areas of the skeleton in which two or more bones meet and

articulate.Thesejointsaresupportedbyavarietyofsofttissuestructures,andtheir

mainfunctionsareeithertofacilitategrowthortoallowmovementbetweenbones

(4).

2.1.2. Classification ofjoints:

Therearemanyclassificationstothejoints;thesimplestclassificationsofjoints relate

to either the range of movement or structural component of the intervening soft

tissues; the most commonly used classification is according to their range of

movement in which they classify to synovial joints with free range of movement,

whereas restricted movement occurs at synarthroses varieties, which can be

subdivided into fibrous and cartilaginous joints(4).

2.1.2.1. Fibrous joints:

Inthefibrousjointsthearticularsurfacesarejoinedbyfibrousconnectivetissue that

allows little movement. Three definable subtypes are sutures, gomphoses and

syndesmoses(4).

2.1.2.2. Cartilaginousjoints:

Inthecartilaginousjointsthearticularsurfacesareunitedbyahyalinecartilage or

fibrocartilage. They are sub divided to: primary cartilaginous joints, or

synchondroses , in which the bones are united by a hyaline cartilage. Primary

cartilaginousjoints,usuallyprovidetemporaryunions,suchasthosepresentduring the

development of a long bone, they permit growth in the length of a bone.

Secondarycartilaginousjointsorsymphysesarelargelydefinedbythepresenceof

aninterveningpadordiscoffibrocartilageinterposedbetweenthearticularhyaline

cartilagethatcoverstheendsoftwobones.Thepadordiscvariesfromafew

millimetres to over a centimeter in width, and the whole region is generally bound

by strong, tightly adherent, dense connective tissues; symphysis pubis joint is a

good example for this type of joints (5).

2.1.2.3. Synovial joints:

These are freely moving joints in which the bony articular surfaces arecovered

withsmooth(hyaline)articularcartilageandseparatedbyafilmofviscoussynovial fluid

that serves as a lubricant. Stability of joint is provided by a fibrous capsule (which

usually has intrinsic ligamentous thickenings) and often by internal or external

accessory ligaments(4).

The articular surfaces are covered by articular cartilage comprises a specialized

type of hyaline cartilage, reflecting its embryological base as part of the

cartilaginous ‘model’ of bone in embryonic life. Exceptions include the ACJ,

sternoclavicular and temporomandibular joints, where articulating surfaces are

covered by dense fibrous tissue containing isolated groups of chondrocytes with

little proteoglycan in their surrounding matrix, presumably reflecting their

formation by intramembranous ossification (4).

A fibrous capsule completely encloses each synovial joint, except where it is

interrupted by synovial protrusions. It is composed of interlacing bundles of

parallelfibersofcollagentypeI,andisattachedcontinuouslyroundtheendsofthe

articulating bones. It is usually exhibits local thickenings of parallel bundles of

collagen fibers, called capsular (intrinsic) ligaments, and named by their

attachments. They do little to resist normal movements but become taut at the end

of each normal range of movement(4).

Synovial membrane lines and cover the fibrous joint capsule and exposed

osseous surfaces, intracapsular ligaments, bursae and tendon sheaths. It does not

coverintra-articulardiscsormenisci,andstopsatthemarginsofarticularcartilages

inatransitionalzonethatoccupiestheperipheralfew millimetersofcartilage.The

synovialmembraneconsistsoftwolayers;ahighlycellularintimallayerrestingon a

fibrous and vascular subintimal layer (subsynovial tissue). The function of synovial

membrane is to secrete and absorb a fluid that lubricates the movement between

the articulating surfaces(4).

Synovial fluid occupies synovial joints, bursae and tendon sheaths. In synovial

joints it is clear or pale yellow, viscous and slightly alkaline at rest (the pH lowers

during activity). Fluid volume is low: usually less than 0.5 ml (4).

An articular disc or meniscus can occur between articular surfaces where

congruity (conformity of opposing articular surfaces) is low. The term meniscus

should be reserved for incomplete discs, like those in the knee joint and,

occasionally, in the acromioclavicular joint. Complete discs, such as those in the

sternoclavicular and inferior radio-ulnar joints, extend across a synovial joint,

thereby dividing it structurally into two synovial cavities; they often have small

perforations. The disc in the temporomandibular joint may be complete or

incomplete (4).

Synovial joints are subclassified according to the arrangement of the articular

surfaces and the types of movement in to seven varieties; plane, hinge, pivot,

ellipsoid, saddle and ball & socket joints. In the plane joints, the apposed articular

surfaces are flat or almost flat, and this permits the bones to slide on one another ,

examples of these joints are the sternoclavicular and ACJ. Hinge joints resemble

the hinge on a door, so that flexion and extension movements are possible,

examples of these joints are the elbow, knee, and ankle joints. In pivot joints, a

central bony pivot is surrounded by a bony–ligamentous ring, and rotation is the

only movement possible, the atlantoaxial and superior radioulnar joints are good

examples. Condyloid joints have two distinct convex surfaces that articulate with

two concave surfaces, the movements of flexion, extension, abduction, and

adduction are possible together with a small amount of rotation movement, the

metacarpophalangealjointsorknucklejointsareexamples.Ellipsoidjoints,posses

elliptical convex articular surface fits into an elliptical concave articular surface,

the movements of flexion, extension, abduction, and adduction can take place, but

rotation is impossible, the wrist joint is a good example. In saddle joints, the

articular surfaces are reciprocally concavoconvex and resemble a saddle on a

horse’s back, these joints permit flexion, extension, abduction, adduction, and

rotation. The best example of this type of joint is the carpometacarpal joint of the

thumb. The Ball-and-socket joints, have a ball shaped head of one bone fits into a

socket like concavity of another, this arrangement permits free movements,

includingflexion,extension,abduction,adduction,medialrotation,lateralrotation, and

circumduction, shoulder and hip joints are good examples of this type ofjoint

(6).

2.1.3. Acromioclavicular joint:

ACJ joint is a plane synovial joint and with fibrocartilaginous disc in its

intraarticular space. It is one the joints that connect axial and appendicular

skeletons. The lateral end of the clavicle articulates with the acromion process of

thescapula.Thearticularsurfaces,coveredwithfibrocartilage,areseparatedbyan

incomplete wedge-shaped articular disc, the clavicular surface is a narrow, oval in

shape that faces laterally or inferolaterally and overlaps a corresponding join facet

on the medial acromion border. The long axis is anteroposterior(4,7,8).

ACJfibrouscapsulecompletelysurroundsthearticularmargins.Itislinedbya

synovial membrane and is strengthened superiorly by the acromioclavicular

ligament and the fibres of the attachment of trapezius, posteriorly by the fibres of

attachment of trapezius, and anteriorly by the fibres of attachment of deltoid

muscles. The inferior capsule is often incomplete in later life (4). Its arterial supply

come from the branches of the suprascapular and thoraco-acromial arteries.Is

innervated by branches from the suprascapular and lateral pectoral nerves, which

are branches of brachial plexus (7).

The ACJ is supported by a set of ligaments; superiorly assets by

acromioclavicular ligament (AC), that is a fibrous band extending from the

acromion to the clavicle, which provide the greatest resistance to anteroposterior

displacement of the joint (7).

However,theintegrityofACJismaintainedbyextrinsicligaments,distantfrom

thejointitself.Thekeystoneligamentiscoracoclavicularligament(CC)thatform by a

strong pair of bands extending between coracoid process of the scapula and the

clavicle, anchoring the clavicle to the coracoid process. It resists rotation and

vertical translation of the joint. The CC ligament consists of two ligaments, the

conoid and trapezoid ligaments; the trapezoid part is anterolateral and broad part,

which extend from the upper part of coracoid to the trapezoid line on the inferior

surface of the clavicle. It is almost horizontal, its anterior border is free, and its

posterior border is joined to the conoid part, forming an angle which projects

backwards. The conoid part is posteromedial and is a dense, almost vertical

triangular band. Its base is attached to the conoid tubercle of the clavicle and its

inferiorapexisattachedposteromediallytotherootofthecoracoidprocessinfront of the

scapular notch. which are often separated by a bursa. In addition to augmenting the

AC ligment, the CC ligament provides the means by which the scapula and free

limb are (passively) suspended from the clavicular strut(4,7).

Regarding the movement of ACJ, the acromion of the scapula rotates on the

acromial end of the clavicle. These movements are associated with motion at the

physiological scapulothoracic joint. No muscles connect the articulating bones to

movetheACjoint;theaxio-appendicularmuscles;(deltoidandtrapeziusmuscles),

which attach to and move the scapula cause the acromion to move on theclavicle

(7).

2.2. Acromioclavicular JointPathology:

2.2.1. Acromioclavicularseparation:

Theseinjuriesaretypicallycausedbyadirectblowtotheshoulder,arecommon

athletic injuries, and can be classified into six types according to the radiological

classification originally described by Rockwood et al, represents a continuum of

increasedsofttissueinjury;intypeItheACligamentsaresprained,butthejointis intact.

In addition there is no palpable displacement of the joint itself. Patients present

only by mild pain associated with movement, the radiograph may show mild soft

tissue swelling, but there is no widening, separation, or deformity at the

ACJ.IntypeIIinjuries,theACligamentsaretorn,buttheCCligamentsareintact. In this

type the patient complain of moderate to severe pain at the AC joint. On

examination the distal part of the clavicle will be slightly superior to the acromion

andshouldermotionincreasesthepainsignificantlyatACJ.AbilateralZancaview may

demonstrate that the distal clavicle is slightly elevated, but the CC ligaments

interspace is the same in both the injured and uninjured shoulders(9).

In type III injuries both ligaments AC and CC are torn, but the deltoid and

trapezial fascia are intact. On examination The distal clavicle may be prominent

enough to camp the skin and is unstable in both planes vertical and horizontal.

Patientspresentwithsupportingtheiraffectedupperlimbinadductedandelevated

positiontohelprelievingpain.IntypeIVinjuries,thesamestructuresaredisrupted

asintypeIIIinjuries.Thedistalclavicleisdisplacedposteriorlyintoorthroughthe

trapezius muscle. In type V injuries, the distal attachments of the deltoid and

trapezius to the clavicle are detached from the distal half of the clavicle. The ACJ

is displaced 100% to 300% and a gross separation between the clavicle and the

acromionispresent.TypeVIinjuriesarerareandarecausedbyextremeabduction that

tears the AC and CC ligaments. The distal clavicle is displaced under the coracoid

and behind the conjoined tendons(9).

2.2.2. Acromioclavicular degenerative jointdisease:

As effect of large loads which transmitted through ACJ with its small surface

area, ACJ one of earliest joints start to degenerates; it may start as the second

decade of life. This condition presents pain especially in crossed-chest adduction

movementanddiagnosedbydirectpalpation,radiographicevidenceofosteophytes and

joint-space narrowing, and pain relief with selective acromioclavicular joint

injection(10).

2.3. Previousstudies:

Several methods are used for evaluating ACJ include patient history, physical

examination,selectiveinjections,plainradiography,ultrasonographyandmagnetic

resonance imaging (MRI). Plane radiographs are often the first imaging modality

of examination performed on a person with a suspected shoulder abnormality and

the complex anatomy of the shoulder has led to the development of numerous

radiographic views and techniques, each designed to optimize the evaluation of

specific parts of the shoulder girdle (2, 8,11).

In a study done by Zanc, analyzing 1000 cases of shoulder pain investigated

involvementofACJ.HedevelopedatechniquepreferredinimagingACJbyusing

anAPviewwitha50%decreaseinpenetrancewiththeX-raybeamtiltedcephalad by 10

to 15°. The decrease in penetrance prevents overexposure and the 15° cephalic tilt

helps to remove the scapula from being superimposed onto the acromioclavicular

joint(11).

In study done by Colegate-Stone et al in (2010) studied the morphology of the

ACJ using cadaveric and radiological analysis. They classified ACJ by describing

articular surfaces of the joint to flat, oblique and curved types. Flat and oblique

varieties were more common (39.2 %) and (38.1 %) respectively. The oblique

joints was sub grouped into:oblique anterior, with the most distal end of the

clavicle inclined anteromedially; and oblique posterior, where the most distal end

was inclined posteromedially (8). Fig (2.1).

Fig (1): Shows the three ACJ subgroups

In another study done by De Palma in (1983) upon morphologicalvariation of

the ACJ by studying, 66 cadavers, with main concern on varying anglesoftorsion

of the joint. It suggested to classify ACJ into three groups with respecttothe

inferomedially angulated plane of the joint; type 1 with average angulationof16°;

type 2 with average angulation of 26° and type 3 average angulation of36°.Also

hedescribedanassociationbetweenACJpathologyandtype1jointwhichwas

thoughttobesecondarytoanincreasedshearingforceonthearticularsurface(2,12).

InstudiesdonebyOppenheimerin(1943)andZancain1971theysuggested

thatthelimitsoftheACJspaceinahealthyshouldervarybetween1and3mm

(13,11).

In study done by Petersson & Redlund-Johnell (1983) in Sweden, they

measured ACJ space in standard antero-posterior images of 151 normal subjects,

theyfoundthatthejointspacewassignificantlywiderinmen,noticedalsoahighly

significant reduction of the joint space with age in both men and women. They

reported that in a person’s past 60 a joint space of 0.5 mm or less can consider as

normalfinding,theyfoundalsothatjointspacewiderthan7mminmenand6mm in

women was abnormal(13,14).

Also in a study done by De Palma (1957) he found that the narrowing of the

ACJ space in increasing frequency with age but did not examine the normal limits

of the normal joint space in different ages (12).

InstudydonebyManaster(1997)hereportedthatthenormalACJspacevaries

between(3–8)mm,andthenormaldifferencebetweenrightandleftsidesshould be not

more than 2 – 3 mm(15).

Chapter Three

Materials & Methods

3.1. Studydesign

3. Materials and Methods

This is a descriptive cross-sectional study.

3.2. Study area:

The study was conducted at Ribat Teaching Hospital - Khartoum state –

Sudan.

3.3. Study duration:

The study was held during the period between (April 2017 – June 2017).

3.4. Studypopulation:

All individuals underwent radiological study in Khartoum state (Ribat

Teaching Hospital).

3.4.1. Inclusioncriteria:

Individualsunderwentchestorshoulderx-rays,inagegroupbetween(18–70) years

old. Asymptomatic patient not complaining from shoulder pain or trauma in last 6

months, with no deformity or previous surgery in shoulder region and X-ray with

good quality (ACJ with adequate appearance, not superimposed bilateral joints

involvement ispreferable).

3.4.2. Exclusioncriteria:

Age groups less than 18 yrs, more than 70 yrs old. Patient’s with shoulder

disorder (dislocations, fracture, rheumatoid arthritis, osteoarthritis). Previous

surgeries in shoulder region and bad quality X-rays (not fulfill the above criteria).

3.5. Study variables:

Participant gender (male - female), participant age, acromial and clavicular

surfacesshape(flat,curved,oblique),ACJmeasurements(Proximaldistance,distal

distance, midpoint distance, longitudinallength).

3.6. Sampling:

3.6.1. Sample type:

The sample group of this study was selected randomly among Sudanese

population.

3.6.2. Sample size:

100 individual computerized x-ray for shoulder joint showing 200 ACJs.

3.7. DataCollection:

3.7.1. Data Collection tools

Reports and radiographs from the Ribat Radiology Department, through data

collectionsheetdesignedtoincludepersonalinformationandallradiologicalstudy

variables.

3.7.2. Data management

Data were represented by figures, tables, charts and pie charts.

3.8. Statisticalanalysis:

By using SPSS (Social Package for Statistically Sciences) version 22, gender

comparison – was done using t- test, age group comparison using Anova test.

3.9. Ethical clearance:

A permission was taken from the review board and Research and Ethical

Committee in the National Ribat University – Faculty of Graduate Studies and

research.

Chapter

FourResults

4. Result

The total number of 100 subjects underwent the study, among them 55 (55%)

subjectwheremales,whereas45(45%)females.Atotalnumberof200ACJ(right & left

sides) were studied carefully, as shown in table (4.1) and Fig(4.1).

Table (4.1): Shows gender distribution of study group.

Gender Frequency Percent

Male 55 55 %

Female 45 45 %

Total 100 100 %

Gender

Fig (4.1): Shows gender distribution of study group.

Male

Studygroupagewasrangedbetween18-70yrs,withagemean43.19yrs.The

participants were catograzied into five age groups as shown in table (4.2) and Fig

(4.2), the most abundant age groups were (18-28) and (29-39) yrs each of them

represent (23%) of the study group. The reliability of data collected was assessed

using Chronbach alpha test; which gave a high degree of reliability(.739).

Table (4.2): Shows the age groups distribution of study participants

Age group (yrs) Frequency Percent

18-28 23 23.0

29-39 23 23.0

40-50 20 20.0

51-61 13 13.0

62-70 21 21.0

Total 100 100.0

Fig (4.2): Shows the age groups distribution of study participants.

AstheACJcomposedoftwoarticularsurfacesacromial,clavicularends,and

according to their articular surfaces shape, the ACJ were classified into nine types

Flat/Flat, flat/curved, flat/oblique, oblique/oblique, oblique/flat, oblique/curved,

curved/curved, curved/flat and curved/ oblique type as shown in figs (4.4) (4.7) ــ.

Thestudyfoundtheflat/curvedtypein49joints(24.5%),flat/flattypein36(18

%)joints,oblique/curvedtype24(12%),curved/flatin23(11.5%),curved/curved

in21(10.5%),oblique/obliquein19(9.5%),oblique/flatin13(6.5%),flat/oblique in 10

(5 %), curved/oblique in 5 (2.5 %) of joints as shown in table (4.3) and fig (4.3).

Therefore the most common types observed in the study were flat/curved type (24.5

%) followed by flat/flat type (18%).

Table (4.3): Shows the distribution of ACJ type.

Joint type Frequency Percent

Flat & Curved 49 24.5

Flat & Flat 36 18.0

Oblique & Curved 24 12.0

Curved & Flat 23 11.5

Curved & Curved 21 10.5

Oblique & Oblique 19 9.5

Oblique & Flat 13 6.5

Flat & Oblique 10 5.0

Curved & Oblique 5 2.5

Total 200 100.0

Fig (4.3): Shows the distribution of ACJ types

Fig (4.4): Shoulder X-ray, shows flat/ curved type of the right ACJ (arrow)

Fig (4.5): Shoulder X-ray, shows curved/ flat type of the left ACJ (arrow)

Fig (4.6): Shoulder X-ray, shows flat/ flat type of the right ACJ (arrow)

Fig (4.7): Shoulder X-ray, shows oblique/ curved type of the left ACJ (arrow)

Thecomparisonbetweenthedistributionofdifferenttypesofrightandleftsides of

ACJ revealed that the flat – curved type was the commonest type in both the

rightandleftsides23(23%),26(26%)respectivelyasshownintable(4.4)andfig

(4.8)

Table (4.4): Shows distribution of ACJ types among right & left sides

ACJ

Right ACJ Left ACJ

Frequency Percent Frequency Percent

Flat-Flat 19 19 18 18

Flat-Oblique 5 5 4 4

Flat-Curved 23 23 26 26

Oblique-Oblique 10 10 10 10

Oblique-Flat 7 7 5 5

Oblique-Curved 13 13 10 10

Curved-Curved 10 10 11 11

Curved-Flat 10 10 14 14

Curved-Oblique 3 3 2 2

Total 100 100 100 100

leftACJ RightACJ

30

25

20

15

10

5

0

Axis Title

Fig (4.8): Shows the distribution of ACJ types among right & left sides

As the result of studying the shapes of acromial and clavicular each side

separately and correlate their shapes (Flat, Oblique, curved) distribution in based

on the gender of study subject, the study found that the most common type in

acromialendonbothsides(right,left)wasFlatinbothgenderbutwithasignificant

difference among them (male, female) (52.7%, 40%), (56.6%, 37.8%).

respectively. While curved type was commonly found in clavicular end in both

sides (right, left) & gender (male, female) (45.5.7%, 46 %), (52.7%, 42.2%)

respectively as shown in table (4.5) and Figs (4.9),(4.10).

1010

Pe

rce

nta

ge

Table: (4.5): Shows the distribution of ACJ articular end shape according to

the gender and side.

Shape

Acromial Clavicular

Male Female Male Female

Rt Lt Rt Lt Rt Lt Rt Lt

Flat

52.7%

56.4%

40.0%

37.8%

32.7%

30.9%

36.0%

42.2%

Oblique

30.9%

23.6%

28.9%

28.9%

21.8%

16.4%

18.0%

15.6%

Curved

16.4%

20.0%

31.1%

33.3%

45.5%

52.7%

46.0%

42.2%

Distribution of right ACJ articular end shape type among gender

52.7%

0% 10% 20% 30% 40% 50% 60%

Curved Obliuqe Flat

Fig (4.9): Shows distribution of right ACJ articular end shape type among

gender

Art

icu

lare

nd

s

Acr

om

ial

Cla

vicu

lar

46.0 %

18.0%

36.0%

45.5%

21.8%

32.7%

31.1%

28.9%

40.0%

16.4%

30.9%

Distribution of left ACJ articularend shape type among gender

56.4%

0.0% 10.0% 20.0% 30.0% 40.0% 50.0% 60.0%

Curved Obliuqe Flat

Fig (4.10): Shows distribution of left ACJ articular end shape type among

gender

As a result of studying 200 ACJs on both right and left sides among different

age groups the mean proximal distance (PD) measures was 5.09 millimeter (mm)

rangedbetween(1.9–8.00),distaldistance(DD)meanwas4.08mm(1-7.20),the

integral ACJ space – literature method (ISD-LM) as calculated in literature using

PD&DDwas4.58mm(1.45-7.60).Basedonthedifferentjointarticularsurface shape

and their effect on integral space and for more accuracy; middle point

distance(MPD)ofjointsweremeasuredandtheintegralspacedistance(ISD)using three

distance was calculated. The MPD mean was 3.68 mm (1.10 – 7.20), ACJ integral

space using three ACJ measures (PD, DD, and MPD) was 4.28 mm(1.33

– 7.47). The mean longitudinal length (LL) of the joint was 10.63 ranged between

(6.50 -15.10) as shown in the table (4.6), fig (4.11).

Art

icu

lar

en

ds

Acr

om

ial

Cla

vicu

lar

Table (4.6): Shows ACJ distances measurements in (mm)

ACJ Measures Mean Minimum Maximum

PD 5.09 1.90 8.00

DD 4.08 1.00 7.20

MPD 3.68 1.10 7.20

ISD- LM (PD,DD) 4.58 1.45 7.60

ISD(PD,

DD,MPD) 4.28 1.33 7.47

LL 10.63 6.50 15.10

Figure (4.11): Shoulder X- ray, shows left ACJ measurements (as labelled PD,

MPD, DD)

On studying the ACJ by different measurements among study age groups, the

mean of PD, DD and MPD was significantly decreasing when age advanced, as

shownintable(4.7)andfig(4.12).IncontrasttheLLshowedanincreasewithage

advancement, as shown in table (4.7), fig(4.13).

Table (4.7): Shows the means of ACJ measurement among study age groups

(mm).

Age group 18-28 29-39 40-50 51-61 62-70

Frequency 46 46 40 26 42

PD 6.15 5.62 4.92 4.42 3.91

DD 4.88 4.34 3.82 3.42 3.55

* ISD- LM 5.51 4.98 4.37 3.92 3.73

MPD 4.47 3.66 3.65 3.06 3.26

** ISD 5.17 4.54 4.13 3.63 3.57

LL 10.17 10.42 10.77 10.86 11.09

7.00

6.00

5.00

4.00

3.00

2.00

1.00

0.00 PD DD MPD

18-28 29-39 40-50 51-61 62-70

Study age groups (yrs)

Fig (4.12): Shows the means of ACJ (PD, DD and MPD) measurements

among study age groups.

Mea

ure

s in

(m

m)

11.20

11.00

10.80

10.60

10.40

10.20

10.00

9.80

9.60

11.09

18-28 29-39 40-50 51-61 62-70

Study age groups

Fig (4.13): Shows means of ACJ (LL) measures among study age groups.

By comparing the means of ISD-LM and ISD using unpaired t test, there was

asignificantdifferencebetweenISD-LMmeanandISD(4.556±0.1025N=200),

(4.285±0.0724N=200)respectively(Pvalue=0.0312(,asshowninfig(4.14).

ISD-LM ISD

Fig (4.14): Shows the means of ISD- LM & ISD comparison using unpaired t

test.

LL

mea

surs

in

(m

m)

AC

J sp

ace

(mm

)

As the result of measuring ISD, on the right and left side of the ACJ, the mean

was 4.26 mm (1.87- 6.65), 4.30 mm (1.54 - 7.23) respectively. By comparing the

means of right & left side using unpaired t test; the study revealed that there was

no significant difference between the right & left side measurements (P value =

0.7808), as shown in table (4.8) and by sorting the study subjects based on their

gender,itwasrevealedthattheISDmeaninmales(n=55)was4.49mm(SD1.11),

whereasinfemales(n=45)was3.99mm(SD1.03)andwhencomparingthemeans of ISD

of males and females using unpaired t test, it was found that the ISD had a

significantdifferencebetweenmaleandfemalegroups(Pvalue=0.0229),theISD was

more wider in males than females, as shown in table(4.8).

Table (4.8): Shows the means of ISD measurements among study age groups

according to gender and side.

Gender Male (n=55) Female (n=45) All

Means

(SD)

Mean

(SD)

Mean

(SD)

Right Mean

(SD)

Left Mean

(SD)

ACJ

Space

4.4945 (1.11)

3.9930 (1.03)

4.2635 (1.06)

4.3066 (1.13)

Chapter

FiveDiscussio

n

5. Discussion

Adescriptivecross-sectionanalyticstudyunderwent100subjects,examining 200

ACJs (right & left). The main objective of this study is to investigate the

radiologicalmorphologyofnormalACJanatomyamongtheSudanesepopulation.

ThepresentstudyhadclassifiedthemorphologyofACJintoninetypesdepending

ontheirarticularsurfacesshape(acromial/clavicular)namelyflat/flat,flat/curved, flat/

oblique, oblique/ oblique, oblique/ flat, oblique/ curved, curved/ curved, curved/

flat and curved/ oblique type. Additionally elaborated more regarding the

morphological classification, when compared with Colegate -Stone et al study in

(2010), which classified them into three main types; flat, oblique and curved,

further subdivided the oblique type by the inclination angle of the distal end of

clavicle either anteromedial or posteromedial. Accordingly, there were no

significantdifferencesinthedistributionofACJtypes.Incontrastwiththispresent

studyshowedthatflat/curvedtypewasthemostcommontype,followedbyflat/flat and

oblique/ curved. On the other hand, both studies found that there was no significant

difference in ACJ types between the right and leftjoints.

Another significant observation in this study that the most common type of

theacromialendonbothsides(right&left)wasflatinbothgender(male&female)

withasignificantdifferenceamongthem.Whilecurvedtypewascommonlyfound

intheclavicularendonbothsides&gender whichwasnotmentionedinliterature

previously. This study found that the ACJ spaces were decreasing when the age

advanced and supporting the results of De Plama, Oppenheimer and Zanc studies.

Moreover, as the result of this study considered to correlate the space measures in

respect to both age and gender. It was found that ACJ space was wider in men.De

Palma (1957) observed that the narrowing of ACJ space was increasing with age.

However,hedidn’texaminethenormallimitsofnormaljointspace,withdifferent ages

therefore were not investigated. Oppenheimer in (1943) and Zanca in1971

suggested that the limits of the ACJ space in a healthy shoulder varied between 1

and 3 mm without considering variables (age and sex).

All the studies discussed previously, determined ACJ space considering

superior and inferior ends of the joint to measure the integral space (ISD- LM).

Adopting the same literature methods the present study found that ISD- LM was

4.58mm(1.45-7.60),with5.09mm(1.9–8.00)PD,DD4.08mm(1-7.20)which

showed the difference in ISD- LM means between studies. This study agrees with

Petersson & RedlundJohnell study, in light of ISD- LM was not exceeding the

pathological limit. Further more when comparing the means of PD & DD in this

study,itdemonstratedthatthePDwasnoticeablywiderthanDD,compatiblewith what

stated in Petersson & Redlund-Johnell study, which resulted the ACJ mean of 3.1

(±0.8) mm, concerning proximal and distal ends were 3.7 (±1.0), 2.6 (±0.6)

respectively. Their study concluded also that when ACJ space exceeding 7 mm in

men and 6 mm in females, often associated with a pathological complication.

Another study done by Manaster (1997) reported that the normal ACJ integral

space was 5.5 (3 – 8) mm, and the normal space difference between right and left

sides should be not more than 2 – 3mm.

Aninterestingcontributionofthisstudywasconcerningthesidesandgenders

ininvestigatingACJmeans.ConsequentlytheresultofmeasuringISD,ontheright

andleftsideoftheACJ,showedthatISDmeanwere4.26mm(1.87-6.65)and

4.30mm(1.54-7.23)respectively,examiningthesemeansrevealedthattherewas no

significant difference between the right & left side measurements (P value 0.7808),

which agree with which mentioned by De Plama, Oppenheimer andZanc studies.

Innovatively a new method of ISD measurement, on behalf of more

uniformityandaccuracymeasurementsofthejointarticularsurfaces.Accordingly, a

new distance point, MPD was consideredin the present study, while measuring

ISD ACJ space. The mean of MPD was 3.68 mm (1.10 – 7.20), which was not

stated previously in literature. Moreover, the ISD was measured using the average

ofPD,DDandMPDshowedthemean4.28mm(1.33–7.47),insteadofusingPD, DD

only which was 4.58 mm (1.45 - 7.60). And when comparing the means ISD- LM

and ISD, it was found that there was a significant difference with (P value 0.0312).

Another the interesting finding was the measurement of LL of the ACJ,

showedthemeanof10.63mm(6.50-15.10).Additionally,incontrasttootherACJ

measures, LL was increasing with the advancedage.

Chapter Sex

Conclusions &Recommendations

6. Conclusions &Recommendations

6.1 Conclusions:

This study classified ACJ into nine types flat/flat, flat/curved, flat/oblique,

oblique/oblique, oblique/flat, oblique/curved, curved/curved, curved/flat and

curved/ oblique type.

The most common type in both male and female was flat/ curved type.

Therewasnosignificantdifferenceintypesanddistancesassociatedwith right

and leftsides.

The PD mean was 5.09 mm (1.9 – 8.00), DD mean 4.08 mm (1- 7.20),

whereas the MPD mean was 3.68 mm (1.10 –7.20).

The LL mean was 10.63 mm (6.50 -15.10).

The ISD mean using (PD, DD, and MPD) was found as 4.28 mm (1.33 –

7.47). On the other hand, the ISD-LM mean as calculated in the literature

using PD & DD was found to be 4.58 mm (1.45 -7.60).

There was a significant difference between the ISD- LM mean andISD.

The mean of the ISD, PD, DD, and MPD was significantly decreasing

when the age advanced while the LL mean showed increasing with

advancedage.

The ISD mean was 4.49 mm (SD 1.11) in males, whereas in females3.99

mm (SD1.03).

There was a significant difference of ISD between the males andfemales.

6.2 Recommendations:

This study recommend that:

Plain shoulder X-ray involving right & left ACJ is valid and useful

investigation modality to diagnose ACJpathologies.

Comparing the right and left side is useful and valid method in detecting

ACJ pathology.

More studies comparing different radiological methods (CT-Scan, MRI),

with larger study sample arerecommended.

A study of symptomatic patients with ACJ pathology isrecommended

More descriptive multicenter studies arerecommended.

Chapter Seven

References

7. References

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Michael A Adams (editor). Gray’s anatomy, 41th ed, London, Elsevier

limited. 2016; Pages 96 -101.

2. DePalma AF. The role of the disks of the sternoclavicular and the

acromioclavicular joints. Clin Orthop 1959; 13:7-12.

3. Salter EG, Nasca RJ, Shelley BS. Anatomical observations of the

acromioclavicular joint and supporting ligaments. Am J Sports Med

1987; 15:199 -206.

4. Henry Gray. Shoulder girdle and arm. In: Simon M Lambert. (editor).

Gray’s anatomy, 41th ed, London, Elsevier limited. 2016; Pages809.

5. Keith L. Moore, Arthur F. Dalley, Anne M. R. Agur. Introduction to

Clinically Oriented Anatomy. In: Clinically Oriented Anatomy, 7th ed,

Philadelphia, Lippincott Williams & Wilkins. 2014; page26.

6. Snell. S. Richard. Introduction. In: Clinical anatomy for medical

students, 9th ed, Boston, Little brown. 1995; page11-13.

7. Keith L. Moore, Arthur F. Dalley, Anne M. R. Agur. Upper limb. In:

Clinically Oriented Anatomy, 7th ed, Philadelphia, Lippincott Williams

& Wilkins. 2014, page796.

8. Colegate-Stone T, Allom R, Singh R et al. Classification of the

morphology of the acromioclavicular joint using cadaveric and

radiological analysis. J Bone Joint Surg Br. 2010;92:743.

9. Rockwood CA Jr, Williams GR, Young D. Disorders of the

acromioclavicular joint. In: Rockwood CA Jr, Matsen F (editors). The

shoulder. Philadelphia, Pennsylvania, USA: Saunders,1998:483–553.

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Miller (editors). Review of orthopedics. 7th ed, London, Elsevier

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11. Zanca P. Shoulder pain: involvement of the acromioclavicular joint

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surgical anatomy. Philadelphia: JB Lippincott, 1983:35-64.

13. Oppenheimer A. Arthritis of the acromioclavicular joint. J. Bone Joint

Surg. 1943; 25:867-870.

14. Petersson CJ & Redlund-Johnell. Joint space in normal

acromioclavicular radiographs. Acta Orthop. Scand, inpress.1938.

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The National Ribat University

Faculty of Graduate Studies & Scientific Research

NORMAL ACROMIOCLAVICULAR JOINT MORPHOLOGY

THESIS

Data collection sheet

SampleNo ParticipantGender M

F Age

ACJMeasures:

Variables Right side Left side

Acromial surface shape Flat Oblique curved Flat Oblique curved

Clavicular surface shape Flat Oblique curved Flat Oblique curved

Proximal distance

Distal distance

Midpoint distance

Longitudinal length

Comment: .......................................................................................................................................................................

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